• Asian Pacific Journal of Cancer Prevention
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• 제15권15호
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• pp.6075-6080
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• 2014

Lung cancer is the leading cause of cancer-related death worldwide. Here we investigated the antitumor effect and mechanism of Zhejiang (Huzhou and Jiande) saffron against lung cancer cell lines, A549 and H446. Using high performance liquid chromatography (HPLC), the contents of crocin I and II were determined. In vitro, MTT assay and annexin-V FITC/PI staining showed cell proliferation activity and apoptosis to be changed in a dose- and time-dependent manner. The inhibition effect of Jiande saffron was the strongest. In vivo, when mice were orally administered saffron extracts at dose of 100mg/kg/d for 28 days, xenograft tumor size was reduced, and ELISA and Western blotting analysis of caspase-3, -8 and -9 exhibited stronger expression and activity than in the control. In summary, saffron from Zhejiang has significant antitumor effects in vitro and in vivo through caspase-8-caspase-9-caspase-3 mediated cell apoptosis. It thus appears to have more potential as a therapeutic agent.

• 대한기계학회논문집B
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• 제27권6호
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• pp.693-700
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• 2003

The effect of the configuration of the nozzle and the impinging surface on the characteristics of the hole-tones has been experimentally investigated. It is found that the plate-tone is a special case of hole-tones, where the hole diameter is zero. The jet velocity range for hole-tones is divided into the low velocity region associated with laminar jet and the high velocity region with turbulent jet. The frequency of the tone is that for the shear layer instability at the nozzle exit or that attainable by a cascade of vortex pairing process with increase of the impinging distance. When the distance is longer than one diameter the frequency decreases to the terminal value near the preferred frequency of the column mode instability, in the range 0.23< $St_d$<0.53, where $St_d$ is the Strouhal number defined by $fd/U_J$, f the frequency, d the nozzle diameter, and $U_J$ the exit velocity. While the convection speed of the downstream vortex, in the present study, is almost constant at low-speed laminar jet, it increases with distance at high-speed turbulent jet. As the frequency increases, the convection speed decreases in the low frequency range corresponding to the preferred mode, in agreement with the existing experimental data for a free jet.

• 대한기계학회논문집B
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• 제31권4호
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• pp.349-356
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• 2007

The present study investigated local heat/mass transfer characteristics on the tip of the rotating turbine blade with various incoming flow incidence angles. The experiments are conducted in a low speed annular cascade with a single stage turbine. The blade has a flat tip with a mean tip clearance of 2.5% of the blade chord. The incoming flow Reynolds number is $1.5{\times}10^5$ at design condition. To examine the effect of off-design condition, the experiments with various incidence angles ranging between $-15^{\circ}$ and $+7{\circ}$ were conducted. A naphthalene sublimation method is used to measure detailed mass transfer coefficient on the blade. The results indicated that the incidence angle strongly affects the behavior of tip leakage flow around the blade tip and consequently plays an important role in determining heat transfer characteristics on the tip. For negative incidence angles, the heat/mass transfer in the upstream region on the tip decreases by up to 20%. On the contrary, for positive incidence angles, much higher heat transfer coefficients are observed even with small increase of incidence angle.

• 생약학회지
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• 제40권1호
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• pp.77-81
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• 2009

Abies nephrolepis(Pinaceae) extracts were tested for determined immune system regulating activity based on antiinflammatory activity, antioxidant activity and anti-proliferative effect on HeLa cell line. The A. nephrolepis extracts increased dose-dependently anti-proliferation of HeLa cell line. The DM fraction of the extracts having anti-proliferatative effects of HeLa cell line was fractionalized four subfractions($D1{\sim}D4$). Inflammation-induced NO production was inhibited by D2 and D4 in LPS-activated RAW264.7 macrophages. And also, this fractions showed antioxidant activity examined by DPPH radical scavenging effects. These results suggest that the potential use of DM fraction of A. nephrolepis in chemoprevention and regulation overproduction of NO on pathogenic conditions. The mechanism of the inflammatory effects, however, must be evaluated through various parameters in the induction cascade of NO production.

• 대한기계학회논문집B
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• 제25권3호
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• pp.442-450
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• 2001

Experiments were carried out on agglomeration of bipolarly charged particles in an alternating current electric field. Laboratory-scale setup was built and experiments were conducted at atmospheric condition. DOS(Di-octyl Sebacate) particles with 100% purity were generated by an atomizer. The particles were branched into two, each of which passed through a wire-to-plate type charging section where a positive or a negative DC high voltage was applied and was charged positively or negatively. These bipolarly charged particles together passed through an agglomeration section where an $\pm$20kV AC power was applied between two plates. The resident time in the agglomeration section was adjusted as l sec. Particle sampling was made by a cascade impactor (MOUDI). The effect of agglomeration system on the reduction ratio of particles below l ㎛ was 42∼45%. Effect of AC frequency on the particle size distribution was found insignificant.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.110.3-111
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• 2003

In the previous studies, we have reported that NQ30l, a synthetic l,4-naphthoquinone derivative, displayed a potent antithrombotic activity, and that this might be due to antiplatelet effect, which was mediated by inhibition of cytosolic $Ca^{2+}$ mobilization in activated platelets. In the present study, the effect of NQ301 on arachidonic acid cascade in activated platlets was examined. NQ301 concentration-dependently inhibited washed rabbit platelet aggregation induced by collagen (10 $\mu$g/ml), arachidonic acid (100 $\mu$M) and U46619 (1 $\mu$M), a thromboxane $A_2$receptor agonist, with $IC_50$ values of 0.60$\pm$0.02, 0.79$\pm$0.04 and 0.58$\pm$0.04 $\mu$M, respectively. (omitted)

• 동의생리병리학회지
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• 제18권2호
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• pp.490-495
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• 2004

Brain cells produce cytokines and chemokines during the inflammatory process of many neuronal diseases both in animal models and in patients. Inflammatory cytokines are the main responsible for the onset of inflammatory cascade. During the past decade, a growing corpus of evidence has indicated an important role of these cytokines in the development of brain damage. ZhenganXifeng-tang (ZGXFT) is a Korean herbal prescription, which has been successfully applied for the treatment of various neuronal diseases. However, its effect in experimental models remains unknown. Astrocytes are predominant neuroglial cells of the central nervous system and are actively involved in cytokine-mediated events in inflammatory disease. An inflammatory response associated with β-amyloid (Aβ) and interleukin (IL)-1β is responsible for the pathology of inflammation disease. To investigate the biological effect of ZGXFT, the author examined cytotoxicity, effect of cytokines (IL-6 and IL-8) secretion and expression of cyclooxygenase-2 (COX-2) on human astrocytoma cell line U373MG stimulated with IL-1β plus M fragment 25-35 (Aβ [25-35]). ZGXFT by itself had no effect on cell viability on human astrocytoma cells. The secretion of IL-6 and IL-8 was inhibited by pre-treatment with ZGXFT in human astrocytoma cells. In addition, the expression of COX-2 was induced by IL-1β plus AB[25-35] and was partially inhibited by treatment with ZGXFT. The author demonstrates the regulatory effects of inflammatory reactions by ZGXFT in human astrocytes for the first time and suggest the anti-inflammatory effect of ZGXFT may reduce and delay pathologic events of inflammatory disease.

• 방송공학회논문지
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• 제23권4호
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• pp.559-573
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• 2018

최근 가상현실(VR, Virtual Reality) 등 가장 많은 분야에서 가장 활발히 응용되고 있는 영상매체 중 하나가 전방위 영상 또는 파노라마 영상이다. 이 영상은 다양한 방법으로 획득된 영상들을 스티칭하여 생성하는데, 그 과정에서 스티칭에 필요한 특징점들을 추출하는데 가장 많은 시간이 소요된다. 이에 본 논문은 현재 가장 널리 사용되고 있는 SIFT 특징점을 추출하는 연산시간을 감소하는 것에 목적을 두고 SIFT 특징점들을 추출에 관여하는 파라미터들을 분석한다. 본 논문에서 고려하는 파라미터는 가우시안 필터링에 사용되는 가우시안 커널의 초기 표준편차, 국소극점을 추출하기 위한 가우시안 차영상군의 수, 그리고 옥타브 수의 세 가지이다. SIFT 알고리즘으로는 이 알고리즘을 제안한 Lowe 방식과 컨볼루션 캐스캐이드(convolution cascade) 방식인 Hess 방식을 고려한다. 먼저 각 파라미터 값이 연산시간에 미치는 영향을 분석하고, 실제 스티칭 실험을 수행하여 각 파라미터가 스티칭 성능에 미치는 영향을 분석한다. 마지막으로 두 분석결과를 토대로 성능저하 없이 연산시간을 최소로 하는 파라미터 값들을 추출한다.

• 한국재료학회지
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• 제4권1호
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• pp.9-23
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• 1994

Multitarget bias cosputter deposition(MBCD)에 의해 저온($200^{\circ}C$)에서 NaCI(100)상에 정합$CoSi_2$를 성장시켰다. X-선회절과 투과전자현미경에 의해 증착온도와 기판 bias전압에 따른 각각 silicide의 상전이와 결정성을 관찰하였다. Metal induced crystallization(MIC) 과 self bias 효과에 의해 $200^{\circ}C$에서 기판전압을 인가하지 않은 경우에도 결정질 Si이 성장하였다. MIC현상을 이론 및 실험적으로 고찰하였다. 관찰된 상전이는 $Co_2Si \to CoSi \to Cosi_2$로서 유효생성열법칙에 의해 예측된 상전이와 일치하였다. 기판 bias전압 인가시 발생한 이온충돌에 의한 충돌연쇄혼합(collisional cascade mixing), 성장박막 표면의 in situ cleaning, 핵생성처(nucleation site)이 증가로 인하여 상전이, CoSi(111)우선방위, 결정성은 증착온도에 비해 기판bias전압에 더 큰 영향을 받았다. $200^{\circ}C$에서 기판 bias전압을 증가시킴에 따라 이온충돌에 의한 결정입성장이 관찰되었으며, 이를 이온충독파괴(ion bombardment dissociation)모델에 의해 해석하였다. $200^{\circ}C$에서의 기판 bias전압증가에 따른 결정성변화를 정량적으로 고찰하기 위해 Langmuir탐침을 이용하여 $E_{Ar},\; \alpha(V_s)$를 계산하였다.

• 물과 미래
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• 제27권1호
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• pp.89-99
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• 1994

현재까지 국내의 홍수예측업무는 과거에 수집된 자료집단을 이용한 변수추정에 의하여 시행되고 있으나, 최근 여러 가지 순환추정 알고리즘을 적용한 홍수예측 또는 변수추정에 관한 많은 연구가 이루어지고 있다. 본 논문은 실시간 홍수예측 및 변수추정에 관한 연구로서, 특히 강우-유출모형의 상태 및 매개변수의 동시추정에 관한 추계학적 현상을 고려하였다. 홍수예측에 관한 시스템은 $\phi$ 지수에 의한 유효강우의 산정과 지체효과를 고려한 n개의 비선형 저수지모형에 의한 홍수축적으로 구성하였다. 그리고 변수추정모형과 홍수추적 모형을 상호연계하여 변수를 포함하는 확대 상태-공간모형으로 상태 및 매개변수의 동시추정에 관한 시스템을 구성하였다. 상태-공간모형에 대한 상태 및 변수추정기법으로 GLS 추정과 MAP 추정에 대하여 비교 검토하였다. 모형의 식별을 위한 민감도 분석은 추정변수의 공분산 행렬을 사용하였다.